Susceptor structure for chemical vapor deposition reactor

ABSTRACT

Improved susceptor means for supporting a series of substrates to be coated with a film in a chemical vapor deposition reactor. The susceptor means comprises a supporting frame structure positioned within a reaction chamber surrounded by a source of heat energy. A plurality of separable discrete susceptor slabs, each of which is formed from a material which is capable of absorbing the heat energy emanating from the heat source, are heated to insure uniform eating of the substrates carried by the slabs. The susceptor slabs are supported in a generally vertical orientation at a slight angle to the vertical to insure maintenance of the substrates in recesses formed therein without requiring additional retaining means. The susceptor means is separable from the reaction chamber to facilitate attachment of the susceptor slabs to the frame structure thereof. The susceptor slabs are separable from the frame structure so that the slabs may be horizontally oriented to facilitate loading of substrates therein prior to attachment of the susceptor slabs to the frame structure. The frame structure is operatively connectable with means for rotating the frame structure within the reaction chamber to insure uniform heating of the substrates carried thereby.

United States Patentv [191 Rosier Mar. 12, 1974 1 SUSCEPTOR STRUCTUREFOR CHEMICAL VAPOR DEPOSITION REACTOR [75] Inventor: Richard S. Rosler,Saratoga, Calif.

[73] Assignee: Applied Materials Technology, llnc., Santa Clara, Calif.

22 Filed: Dec. 16, 1971 21 Appl. No.: 208,732

[52] 0.5. CI. 118/48, 118/319 [51] Int. Cl C23c 113/08 [58] Field ofSearch 118/48-49.5,

118/319; ll7/107.l; 204/298, 192; 219/1049; 269/50 [5 6] 7 ReferencesCited UNITED STATES PATENTS 3,699,298 10/1972 Briody 118/48 X 3,594,2277/1971 Oswald l17/l07.l X

2,365,336 l/l968 Folkmann et a1... 118/500 X 3,424,629 1/1969 Ernst eta1. l18/49.1 X 3,460,510 8/1969 Currin 118/48 2,955,566 10/1960 Campbellet a1 118/48 2,453,801 11/1948 Mattern 118/503 X 3,503,368 3/1970Pudliner 118/49.1 X 3,607,368 9/1971 Van Amstel 118/495 X FOREIGNPATENTS OR APPLICATIONS 850,416 10/1960 Great Britain 1 18/500 PrimaryExaminerM0rris Kaplan [57] 1 ABSTRACT Improved susceptor means forsupporting a series of substrates to be coated with a film in a chemicalvapor deposition reactor. The susceptor means comprises a supportingframe structure positioned within a reaction chamber surrounded by asource of heat energy. A plurality of separable discrete susceptorslabs, each of which is formed from a material which is capable ofabsorbing the heat energy emanating from the heat source, are heated toinsure uniform eating of the substrates carried by the slabs.

The susceptor slabs are supported in a generally vertical orientation ata slight angle to the vertical to insure maintenance of the substratesin recesses formed therein without requiring additional retaining means.The susceptor means is separable from the reaction chamber to facilitateattachment of the susceptor slabs to the frame structure thereof. Thesusceptor slabs are separable from the frame structure so that the slabsmay be horizontally oriented to facilitate loading of substrates thereinprior to attachment of the susceptor slabs to the frame structure. Theframe structure is operatively connectable with means for rotating theframe structure within the reaction chamber to insure uniform heating ofthe substrates carried thereby. 1

11 Claims, 6 Drawing Figures PM: rum r5 SUSCEPTOR STRUCTURE FOR CHEMICALVAPOR DEPOSITION REACTOR BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to the field of vapor deposition offilms of various types on substrates. More particularly, the field ofthis invention involves the vapor deposition of epitaxial orpolycrystalline or amorphous films, for example silicon dioxide and likefilms, on exposed surfaces of articles, such as silicon wafer substratescommonly used in the electronics industry. Gaseous chemical reactantsare brought into contact with heated substrates within a reactionchamber, such substrates being supported by susceptor means which absorbheat energy emanating from a heat source, such as a radiant heater,surrounding the reaction chamber.

This invention further relates to the field of improved susceptor meansfor supporting substrates during a chemical vapor deposition reactionand to the field of simplifying loading of substrates into position onsuch susceptor means.

2. Description of the Prior Art While substrates, such as siliconwafers, have been coated heretofore with epitaxial and other films, suchas silicon dioxide or like films, while supported on a susceptorstructure, so far as is known, the specific and improved susceptor meansdisclosed herein is novel. Such susceptor means is designed to produceuniform film coatings on substrates being treated under controlledchemical vapor deposition conditions so that coated substrates of highquality and excellent film thickness uniformity are producible withinclosely controlled limits.

In chemical vapor deposition systems it is highly desirable to carry outthe deposition reaction in a cold wall type reaction chamber. Bymaintaining the reaction chamber walls in the unheated state, such wallsreceive little or no film deposition during substrate coating. Cold wallsystems are additionally desirable because they permit the deposition ofhigh purity films, such as silicon dioxide or like films thereon.Impurities can be evolved from or permeate through heated reactionchamber walls. Because such impurities would interfer with and adverselyaffect the purity of the substrate coating, cold wall reaction chamberspreferably are employed to preclude such impurity evolution orpermeation.

To avoid such problems, chemical deposition processes have beendeveloped which permit heating of a substrate positioned within areaction chamber without simultaneously heating the reaction chamberwalls. Such processes generally involve the use of radio frequency (RF)induction heating ofa one piece conducting susceptor positioned withinthe reaction chamber, the walls of which are formed of non-conducting orinsulating material.

For example, RF heating ofa one piece graphite susceptor positionedwithin a quartz reaction chamber for depositing epitaxial and like filmshas been known generally heretofore, However, such RF heatingtechniques, while the same generally produce the stated objective in acold wall reaction chamber, have several inherent and importantdisadvantages which make the same undesirable under many circumstances.For example, an expensive and bulky RF generator is required which isvery space consuming and which must be located close to the filmdeposition reactor. Also, the high voltage required with the RF coilsproduces substantial personnel hazards, and RF radiation from the RFcoils can and frequently does interfer with adjacent electricalequipment. Also, as noted, a single piece continuous susceptorisrequired which frequently is difficult and expensive to produce.

As noted, such an RF procedure normally requires the utilization of aone piece electrically conducting susceptor for supporting thesubstrates to be heated. That is, such induction type reactors normallyrequire one piece susceptors to insure current flow therethrough and toinsure maximum efficiency of such a reactor. Also, inductance typereactors normally require single piece suscept'ors because electricalarcing would normally result if a susceptor of two or more pieces wereused because of the different potentials which normally would beencountered in the separate pieces of a two-or-more piece susceptor.Inductance type systems require electrical continuity to insureeffective and efficient operative coupling to the generator andtherefore such continuity normally dictates the need to use a one piecesusceptor. Also RF inductance type systems are considerably moreexpensive overall than the illustrative radiation heated systems of thetype with which this this invention is described.

The same general considerations discussed above with respect toinductance type reactors are generally applicable to resistance typeheated reactors as well, and as a result, such resistance heatedreactors also commonly use one piece susceptors.

In applicants assignees McNeilly et al. US. Pat. No. 3,623,712, havingan issue date of November 30, 1971, an improved cool wall radiationheated system is disclosed which was designed to replace the RF andother reaction systems utilized theretofore as exemplified by the priorart of record against said patent. The susceptor means of the presentinvention has been designed as an adjunct improvement for utilization ina cool wall radiation heated reactor of the type disclosed in saidMcNeilly et al patent. However, because of the novelty of itsconstruction, the susceptor means of this invention may be utilized inreactors of types other than the radiant heated reactor disclosed insaid McNeilly et al patent.

SUMMARY OF THE INVENTION This invention relates generally to an improvedsusceptor means for supporting a plurality of substrates in a reactionchamber during a chemical vapor deposition reaction during which anoxide, nitride, metal or other similar epitaxial or polycrystalline oramorphous film is chemically vapor deposited on such substrates, such assilicon and other wafers commonly employed in the electronics industryin the manufacture of integrated circuits, transistors and the like.More particularly, this invention relates to an improved multi-piecesusceptor structure for supporting a plurality of substrates to bechemically vapor deposition coated within a reaction chamber of aradiant heated or other chemical vapor deposition reactor, suchstructure being specifically designed to facilitate loading andunloading of substrates to be coated on the susceptor structure.

Still more particularly, this invention relates to an improved susceptormeans for utilization in a cold wall chemical vapor deposition reactorfor coating substrates with a predetermined type of film. While thisinvention has particular utility in conjunction with a radiation heatedreactor of the type disclosed in said McNeilly patent, and isillustrated and described herein in conjunction with such a reactor, itshould be understood that its utilization in other reactor assembliesalso is contemplated hereby.

This invention has utility in conjunction with coating substrates withvarious types of known films, including epitaxial, polycrystalline andamorphous films. While hereinafter reference is directed by way ofexample primarily to the chemical vapor deposition of epitaxial films,utility of this invention is not restricted to that particularapplication.

The susceptor means of the present invention includes a supporting framestructure on which are re movably supported a series of discretesusceptor slabs each of which is formed from a material which is opaqueto the heat energy emanating from the heat source positioned adjacentthe slabs. As used herein, the term opaque" is intended to includewithin its sepoe those materials which are capable of absorbing energyto produce heat. By way of example herein, the heat source illustratedis of the radiant type which produces radiant energy at a predeterminedwave length in the manner described in said McNeilly et al patent.

In the preferred embodiment disclosed herein, such frame structuresupports a plurality of susceptor slabs in generally circularorientation and the frame structure is surrounded by the heat sourcewhen the susceptor means is positioned in a reaction chamber. Suchdiscrete susceptor slabs may be more easily and less expensivelymanufactured than the large one piece susceptors used heretofore. Whenthe susceptor means is positioned within a reaction chamber, gaseouschemical mixtures, composed of one or more suitable reactants in knownfashion, and as described in detail in said McNeilly et al. patent, areselelctively introduced into the reaction chamber to come into contactwith heated substrates supported on the susceptor slabs connected withthe frame structure. Such substrates are heated by their supportingsusceptor means absorbing energy from the radiant heat source withoutsimultaneously heating the walls of the reaction chamber, which areformed from a material which is transparent to heat energy transmittedat the wave length chosen for the heat source as described in saidMcNeilly et al. patent.

The supporting frame structure perferably is separable from the reactionchamber, either by removing the frame structure from the reactionchamber or by removing the reaction chamber from around the framestructure, so that access may be had to the frame structure to engageand disengage susceptor slabs therewith prior to and following chemicalvapor deposition of films on substrates carried thereby.

Because the susceptor slabs are selectively removable from the framestructure, they may be positioned horizontally when thus removed tosimplify loading of substrates in recesses formed therein. When therecesses are thus filled with the desired number of substrates, the'slab structures may be engaged with the frame structure and the framestructure may then .be reinserted into the reaction chamber, or thereaction chamber may be positioned about the frame sturcture, dependingupon the construction of the particular reactor with which the susceptoris to be utilized. When engaged with the frame structure, the susceptorslabs are generally vertically oriented but are inclined towards thevertical axis of the frame structure so that the substrates aremaintained in the slab recesses without requiring additional retainingmeans therefor.

The frame structure includes a vertical shaft which is operativlyconnectable with means for rotating the frame structure within thereaction chamber to insure uniform heating of the substrates carried bythe susceptor means.

From the foregoing, it should be understood that objects of thisinvention include the provision of im proved susceptor means forutilization in a reactor for chemically vapor depositing films onsubstrates supported thereby; the provision of improved susceptor meansincluding a supporting frame structure carrying a plurality of discretesusceptor slabs each of which is capable of supporting a plurality ofsubstrates to be coated therein; the provision of improved susceptormeans comprising a plurality of separable susceptor slabs which arevertically oriented when the susceptor means is in operative positionand which may be selectively removed from the frame structure andpositioned horizontally to facilitate loading of substrates therein; andthe provision of improved susceptor means for rotatably supportingsusceptor slabs in a generally vertical orientation during heatingthereof in a chemical vapor deposition reactor.

These and other objects of this invention will become apparent from astudy of the following description in which reference is directed to theappended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1' is a vertical sectional viewthrough a chemical vapor deposition reactor showing one embodiment ofthe subject susceptor means positioned therein.

FIG. 2 is a horizontal sectional view through the reactor taken in theplane of line 22 of FIG. 1.

FIG. 3 is a side elevational yiew of a portion of the subject susceptormeans taken in the plane of line 33 of FIG. 2.

FIG. 4 is a partial vertical sectional view through a susceptor slab ofthe subject susceptor means taken in the plane of line 44 of FIG. 3.

FIG. 5 is a vertical sectional view through a chemical vapor depositionreactor showing a modified embodiment of the subject susceptor meanspositioned therein.

FIG. 6 is a horizontal sectional view through the reactor taken in theplane of line 6--6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Several embodiments of radiantheated reactors well suited to carry out an effective chemical vapordeposition procedure are disclosed herein. However, full structuraldetails of such reactors, and their mode of operation, are not describedin detail herein. For a full understanding of the construction andoperation of such a radiant heated reactor of the type illustratedherein, reference is directed to the aforementioned McNeilly et al. US.Pat. No. 3,623,712.

This invention relates specifically to improved susceptor means of thetype particularly well suited for utilization in conjunction with such aradiant heated reactor although, it should be understood, that thesusceptor structure of this invention has utility in other types ofchemical vapor deposition reactors as well.

Two embodiments of the subject susceptor means of this invention aredisclosed herein, each of which is shown operatively positioned within areaction chamber of a radiant heated reactor. Each of such embodimentsis shown incorporated into a cold wall reaction chamber the walls ofwhich are transparent (i.e. essentially non-absorbent) to radiant heatenergy transmitted from a radiant heat source. The source of suchradiant heat in the illustrated embodiments comprises a bank of highintensity lamps, which produce and transmit high temperature heat energyat a wave length which is not intefered with or appreciably absorbed bythe walls of the reaction chamber.

The chemical vapor deposition procedure within the reaction chamber isdescribed in detail in said McNeilly et al. patent and reference isdirected thereto for an understanding thereof. However, it should beunderstood that the reactor with which the subject susceptor means isutilizable is designed to produce various chemical reactions and/orthermal pyrolysis reactions to deposit a variety of selective types ofepitaxial, polycrystalline or amorphous films, such as silicon, galliumarsenide phosphide, silicon nitride and silicon dioxide, as well asmetal films such as molybdenum, titanium, zirconium and aluminum, inaccordance with known chemical vapor deposition reactions in thepresence of heat.

In that regard, the heat source illustrated desirably comprises a bankof tungsten filament, quartz-iodine high intensity lamps which arecommercially available as described in said McNeilly et al. patent. Suchlamps are capable of producing high filament temperatures in the rangeof 5,000 to 6,000 F. The lamps chosen desirably are selected from thetypewhich produce maximum radiant heat energy in the short-wave lengthrange, preferably approximately 1 micron. Such radiant heat energy insuch short-wave lengths passes through material found suitable fordefining the walls of the reaction chamber, of which quartz ispreferred.

Reactors of the type described briefly herein have been effectively usedfor producing films of the type previously identified with filmthickness uniformity of plus or minus 5 percent from substrate tosubstrate within a given run. Highly effective results can be insuredbecause operating temperatures can be controlled closely and uniformlywith the heat source described.

Referring first to the embodiment illustrated in FIGS. 1 through 4, itshould be understood that the reactor structure is shown in generallyschematic fashion and is intended to be enclosed within a surroundingcabinet (not shown) in and on which the necessary gaseous reactant flowcontrols, electrical power sources, and other attendant mechanisms areto be housed and mounted. For purposes of understanding the subjectinvention, only those portions of the reactor necessary to illustratethe environment in which the improved susceptor means of this inventionis utilized have been illustrated. It should be understood that thoseportions of the reactor illustrated are intended to be supported withinthe aforementioned cabinet in any suitable fashion.

The reactor illustrated in FIG. I is generally designated l and isdefined by an enclosure generally designated 2 within which theaforementioned heat source,

generally designated 3, is positioned. Such heat source is defined by abank of high intensity lamps capable of producing and transmittingradiant heat energy at the short-wave length noted previously. Each ofsuch lamps is designated 4 and is positioned in a cylindrical ringshaped lamp mounting block 5 supported on a plate 6 of enclosure 2.

Lamps 4 are positioned in a series of semi-spherical sockets 7 which arearranged in vertically spaced rows extending in parallel relationshipabout the inner periphery of the block 5. The lamp mounting blocksurrounds the reaction chamber of the reactor to be described and isprovided with means for cooling the same in the form ofa helical coil 8which surrounds the block and through which a cooling fluid, such aswater, is circulated. The cooling fluid enters coil 8 at one end 9thereof and exits at the other end 1 1 thereof. Cooling air also may beintroduced through the lamp mounting block through the lamp sockets ifdesired. The inner surface 12 of the lamp block is highly polished formost effective heat radiation.

The heat source thus described surrounds the reaction chamber of thereactor which, in the embodiment shown in FIG. 1, is defined by a quartzbell jar 13 which for carrying away spent reaction gases from thereaction chamber following a chemical vapor deposition reaction therein.

At its upper end, the reactor is provided with a supporting base plate19 which rests upon a peripheral shoulder 21 formed as part of theapertured plate 17 of the enclosure 2. Interposed between the base plate19 and flange 16 of bell jar 13 is a seal member 22 which provides a gastight seal therebetween. Such seal member 22'is formed of any heatresistant material capable of withstanding the substantial temperaturescreated within the reaction chamber.

Suitable chemical gaseous reactants of known type are selectivelyintroducible into the reaction chamber through a conduit 23 which ispositioned in and extends through an opening'24 provided in base plate19. Conduit 23 is operatively connected with any suitable source ofgaseous reactants (not shown) so that such reactants may be metered inknown fashion into the reaction chamber for effecting chemical vapordeposition reactions on substrates positioned therein.

Base plate 19 includes a central boss 26 in which a bearing member 27 ispositioned and through which a portion of the susceptor means 14extends. In that regard, such susceptor means includes a verticallyextending shaft 28 which extends through bearing 27. Shaft 28 has anenlarged retaining ring 29 adjacent one end thereof which rests upon thebearing 27 and properly positions the shaft within the reaction chamberin alignment with the heat source described previously.

As noted by the arrow in FIG. 1, shaft 28 preferably is operativelyconnectable with any suitable means (not shown) to effect rotationthereof within the reaction chamber at any predetermined rate ofrotation.

It should be understood that base plate 19, shaft 28 and the remainderof the susceptor means to be described are removable as a unit fromwithin the belljar by raising the base plate upwardly in the directionsof the arrows shown in FIG. 1. Such movement relative to the reactionchamber is effected to simplify loading and unloading of substrates onthe susceptor means inthe manner to be described.

In addition to shaft 28, the susceptor means includes a supporting framestructure, generally designated 31, which in the embodiment illustratedcomprises a pair of horizontally extending plate members 32 and 33 whichare welded or otherwise secured to the shaft at vertically spacedlocations thereon. As seen in FIG. 3, upper plate 32 is generallyoctagonal in peripheral configuration while bottom plate 33 is generallycircular in peripheral configuration. The configuration of the top plate32 is determined in accordance with the particular size and capacity ofthe susceptor means and the octagonal configuration is utilized becauseeight structures for supporting substrates to be coated are engagedtherewith in the embodiment shown.

In that regard, such substrate supporting structures comprise a seriesof thin susceptor slabs 36, eight in number in the embodiment shown,each of which is designed to support therein a plurality of substrates,designated S, which may be silicon, gallium arsenide, quartz, ceramic ormetal wafers (such as molybdenum or tungsten) of the type commonly usedin the electronics industry to produce semiconductor devices.

As seen in FIG. 3, each susceptor slab 36 is generally rectangular inconfiguration and each comprises means for supporting a plurality ofsubstrates S thereon. in the illustrated embodiment such supportingmeans com prises a plurality of generally circular recesses 37 formed inone surface of the slab, each such recess being provided to receive asubstrate S therein for vapor deposition ofa chemical film thereon. Inthe embodiment shown, five vertically spaced recesses 37 are providedfor receiving five substrates therein. Depending upon the size of thereactor, more than or less than five recesses may be provided in eachsuch slab.

Although substrate receiving recesses have been shown as the means forsupporting substrates on each slab 36, it should be understood thatother supporting means could also be used. For example, the substratescould be supported by small integral projections extending from the slabface at vertically spaced locations thereon.

The susceptor slabs are formed from material which is opaque to the heatenergy generated by the heat source utilized in the reactor and suchslabs may be formed from known materials. such as carbon, siliconcarbide coated graphite, or vitreous carbon. However, any hightemperature material compatible with chemical vapor deposition reactionsmay be utilized for forming the susceptor slabs 36.

The supporting frame structure 31 is provided with I support means forremovably attaching the discrete susceptor slabs thereto. In thatregard, it will be noted that the susceptor slabs are generallyvertically oriented when they are attached to the supporting framestructure. To that end, the diameter or maximum transverse dimension ofthe bottom plate 33 of the frame structure is of larger size than thediameter or maximum transverse dimension of upper plate 32. Thus, thesusceptor slabs are inclined towards the vertical axis of the susceptormeans defined by the axis of shaft 28, at a predetermined degree whichmay be in the range of 2 to 10 relative to the vertical. Thus, thesubstrates positioned within the supporting means defined by recesses 37of the slabs 36 are maintained therein without requiring separateretaining means for that purpose.

The supporting frame structure 31 includes support means for separablyretaining the slabs 36 in connection therewith and, in the embodimentillustrated, such retaining means comprises at least one supporting pegor equivalent structure projecting from at least one of the platestructures 32 and 33 of the supporting frame. In the embodimentillustrated, two spaced supporting pegs, genrally designated 41, projectfrom each of the edges of the octagonal periphery of the upper plate 32of the supporting frame structure. As seen in H0. 3, each susceptor slabis provided adjacent one end thereof with interfitting structure formating with the pegs 41 and in the embodiment illustrated such structurecomprises a pair of recesses or holes 42 therein provided to receivesupporting pegs 41 when such susceptor slab is positioned in engagementwith the supporting frame structure.

It should be understood that, if preferred, the pegs (or some equivalentmeans) could be provided on the bottom plate 33 so that the upper endsof the slabs would rest upon the periphery of the top plate 32 while thebottom ends thereof are'supported by such pegs. Also, under certaincircumstances, depending upon slab size and weight, the bottom plate 32can be eliminated if the upper plate is provided with integral.structure to maintain the slabs at the desired degree of inclinationrelative to the vertical axis of the susceptor means.

In any case, however, the susceptor slabs are designed to be easilyseparable from the supporting frame structure when the susceptor meansis separated from within the reaction chamber in the manner describedpreviously.

Ease of separation of the susceptor slabs from the supporting framestructure 31 is an important feature of this invention in that itgreatly facilitates loading of substrates into the individual susceptorslabs and loading of filled susceptor slabs onto the frame structure.That is, by separating the susceptor slabs from the supporting framestructure and positioning the same in a horizontal orientation,substrates may be placed in the slab recesses 37 easily and rapidlywithout danger of manual touching of the central coating areas of thesubstrates which are being coated. After such substrates have beenloaded in the respective slabs, it is then a simple matter to hook theslabs on the supporting pegs 41 without danger of the individualsubstrates becoming disengaged from their receiving recesses.

While it should be understood that it would also be possible to positionthe substrate supporting slabs on the supporting pegs while the framestructure is in the operative position shown in FIG. 1, it is obviouslya much easier operation to so position the slabs when the framestructure is removed from the reaction chamber for more ready access. 1

Reference is now directed to FIGS. 5 and 6 for a disclosure of amodified embodiment of the subject susceptor means. ln that regard,similar reference numerals are used to identify similar components ofthe reactor described previously with respect to the embodiment of FIGS.1 through 4. A similar heat source 3 is utilized and such heat sourcesurrounds a quartz or like bell jar 13 which corresponds generally tothe previously described bell jar except for the fact that bell jar 13does not include a reactant gas passage 18 at one end thereof.

The principal difference between the susceptor embodiments of FIGS. 1and 5 is that in the FIG.- 1 embodiment the susceptor means 14 dependsdownwardly into the reaction chamber defined by bell jar 13 while in theFIG. 5 embodiment the susceptor means 14 extends upwardly into thereaction chamber defined by the bell jar 13. In that regard, the flange16 of bell jar 13' extends within the heat source 3 and rests upon abase plate 19 which forms an integral part of the plate 6 of enclosure2. Thus, to separate the reaction chamber bell jar from the susceptormeans 14 in the FIG. 5 embodiment, it is merely necessary to elevate thebell jar and remove the same from within the heat source.

The susceptor means of FIG. 5 corresponds generally to that describedpreviously in that the same includes a vertical shaft 28 which isoperatively connectable with means for rotating the same (not shown).Shaft 28 extends upwardly through boss 26 provided in supporting plate19 and through the bearing 27 extending through the boss in the mannerdescribed previously. Within the reaction chamber,shaft 28 is providedwith an enlarged retaining ring 46 which supports the supportingframework 3l of the susceptor means on bearing 27. Such supportingframework includes an upper octagonally shaped plate member 32 and alower plate member 33 which corresponds generally to the plate 33described previously except that plate 33 also is formed with anoctagonal periphery as seen in FIG. 6.

The upper plate 32 is provided with supporting pegs 41 projecting fromthe eight edge portions thereof as also seen in FIG. 6 and such pegsremovably retain and support eight susceptor slabs 36 in the mannerdescribed previously at a predetermined angle relative to the verticalaxis defined by the axis of shaft 28. The octagonal lower plate 33 isselectively used in place of a circular lower plate to impart a morestable engagement of the lower ends of the susceptor slabs with suchlower plate.

With the embodiment of FIG. 5, while the susceptor slabs are easilyremovable from the supporting frame 31 when the bell jar 13 is removed,it is normally not necessary to elevate the supporting frame structurefrom within the heat source in that sufficient clearance is providedbetween the inner surface 12 of lamp block 5 and the supporting framestructure 31 when the bell jar is removed to permit the susceptor slabsto be hooked on the supporting pegs. However, if desired, the shaft 28may be slidably positioned within bearing 27 to permit elevation of thesupporting framework relative to the heat source so that more readyaccess to the supporting pegs may be had to further facilitate engagement or removal of the susceptor slabs relative to the supportingframework.

In the embodiment of FIG. 5, the gaseous reactants are introduced intoand removed from the reaction chamber bell jar 13' through conduits 47and 48 which pass through openings 49 and 51 provided in the base platestructure 19 in the manner seen in FIG. 5. Thus,

suitable gaseous reactants may be selectively introduced into and spentreaction products withdrawn from the reaction chamber in known fashion.

As mentioned, preferably each of the susceptor embodiments of FIGS. 1and 5 is connectable with means (not shown) for rotating the supportingframework thereof. While such rotation is not required under allcircumstances, relatively slow rotation, in the range of approximately10 to 15 revolutions per minute, has been found effective to insureuniform heating of the susceptor slabs 36 and the plurality ofsubstrates S carried thereby.

Having thus made a full disclosure of various embodiments of improvedsusceptor means for supporting substrates to be coated during a chemicalvapor film deposition reaction, reference is directed to the appendedclaims for the scope of protection to be afforded thereto.

I claim:

1. In a radiant heated reactor for effecting a chemical vapor filmdeposition reaction on heated substrates positioned therein and heatedthereby which includes A. a radiant heat source, for producing andtransmitting radiant heat energy,

B. means defining a reaction chamber, for receiving therein thesubstrates to be coated, adjacent said heat source and generallysurrounded by the same, said chamber being formed from a material whichis transparent to radiant heat energy produced by said radiant heatsource, and

C. conduit means for introducing gaseous reactants into said reactionchamber and for withdrawing the spent reaction gases from said chamber,

the improvement comprising susceptor structure to facilitate loading andunloading of a plurality of substrates to be coated in said reactionchamber defined y D. improved multi-piece susceptor means within saidreaction chamber for supporting a plurality of substrates thereon duringoperation of said reactor, comprising 1. a generally verticallyextending supporting frame structure positioned within said reactionchamber and selectively separable therefrom, and

2. a plurality of elongated susceptor slabs separably supported ingenerally vertical orientation by said frame structure generally inalignment with said heat source,

3. means provided on said frame structure for separably retaining saidsusceptor slabs in engagement therewith,

4. each said susceptor slab including structure cooperable with saidmeans on said frame structure for separably retaining said slabs engagedtherewith,

5. each such slab being formed from a material which is opaque to saidradiant heat energy and which absorbs the same and is heated thereby,

6. all of such slabs having means on a surface thereof facing said heatsource for separably supporting thereon a plurality of substrates to becoated,

7. each such slab being selectively separable from said frame structureand being removable from said reaction chamber so that a plurality ofsubstrates to be coated may be positioned in engagement with or removedfrom such slab while the llll same is out of said reaction chamber,whereby loading and unloading of said reaction chamber is facilitated.

2. The susceptor means of claim 1 in which said supporting framestructure includes support means for inclining each of such susceptorslabs at a predetermined angle relative to the vertical axis of saidsupporting frame so that substrates positioned in engagement with saidmeans on said surfaces are maintained thereon by such inclination ofsaid slabs without requiring additional retaining means.

3. The reactor of claim 1 in which said reactor further includes E.means operatively connected with said supporting frame structure of saidsusceptor means for rotating said frame structure about its verticalaxis within said heat source during chemical vapor deposition of film onsaid substrates carried by said susceptor slabs.

4. The reactor of claim 3 in which said susceptor slabs are supported bysaid supporting frame in a generally circular pattern surrounding thevertical axis thereof.

5. The reactor of claim 1 in which said means defining said reactionchamber depends from a base plate of said reactor and is supportedthereby, and in which said susceptor means is suspended within saidreaction chamber from said base plate.

6. The reactor of claim 1 in which said means defining said reactionchamber projects upwardly from a base plate of said reactor and issupported thereby, and in which said susceptor means projects upwardlyinto said reaction chamber.

7. The susceptor means of claim 1 in which said supporting framestructure comprises a. a vertically extending shaft, b. verticallyspaced plate members secured to said shaft, and i c. retaining means onat least one of said plate members for removably supporting suchsusceptor slab on said frame structure.

8. The susceptor means of claim 7 in which said retaining meanscomprises at least one peg projecting from said one plate member, saidsusceptor slab having at least one hole therein for receiving asupporting peg therein when such slab is supported by said frame member.

9. The susceptor means of claim 8 in which each such peg is formed onthe upper plate of said vertically spaced plate members.

10. The reactor of claim 5 in which said susceptor means is verticallymovable from said reaction chamber so that said susceptor slab may bereadily separated from said supporting frame structure.

11. The reactor of claim 6 in which said reaction chamber is removablefrom around said susceptor means so that said susceptor slab may bereadily separated from said supporting frame structure.

1. In a radiant heated reactor for effecting a chemical vapor filmdeposition reaction on heated substrates positioned therein and heatedthereby which includes A. a radiant heat source, for producing andtransmitting radiant heat energy, B. means defining a reaction chamber,for receiving therein the substrates to be coated, adjacent said heatsource and generally surrounded by the same, said chamber being formedfrom a material which is transparent to radiant heat energy produced bysaid radiant heat source, and C. conduit means for introducing gaseousreactants into said reaction chamber and for withdrawing the spentreaction gases from said chamber, the improvement comprising susceptorstructure to facilitate loading and unloading of a plurality ofsubstrates to be coated in said reaction chamber defined by D. improvedmulti-piece susceptor means within said reaction chamber for supportinga plurality of substrates thereon during operation of said reactor,comprising
 1. a generally vertically extending supporting framestructure positioned within said reaction chamber and selectivelyseparable therefrom, and
 2. a plurality of elongated susceptor slabsseparably supported in generally vertical orientation by said framestructure generally in alignment with said heat source,
 3. meansprovided on said frame structure for separably retaining said susceptorslabs in engagement therewith,
 4. each said susceptor slab includingstructure cooperable with said means on said frame structure forseparably retaining said slabs engaged therewith,
 5. each such slabbeing formed from a material which is opaque to said radiant heat energyand which absorbs the same and is heated thereby,
 6. all of such slabshaving means on a surface thereof facing said heat source for separablysupporting thereon a plurality of substrates to be coated,
 7. each suchslab being selectively separable from said frame structure and beingremovable from said reaction chamber so that a plurality of substratesto be coated may be positioned in engagement with or removed from suchslab while the same is out of said reaction chamber, whereby loading andunloading of said reaction chamber is facilitated.
 2. The susceptormeans of claim 1 in which said supporting frame structure inCludessupport means for inclining each of such susceptor slabs at apredetermined angle relative to the vertical axis of said supportingframe so that substrates positioned in engagement with said means onsaid surfaces are maintained thereon by such inclination of said slabswithout requiring additional retaining means.
 2. a plurality ofelongated susceptor slabs separably supported in generally verticalorientation by said frame structure generally in alignment with saidheat source,
 3. means provided on said frame structure for separablyretaining said susceptor slabs in engagement therewith,
 3. The reactorof claim 1 in which said reactor further includes E. means operativelyconnected with said supporting frame structure of said susceptor meansfor rotating said frame structure about its vertical axis within saidheat source during chemical vapor deposition of film on said substratescarried by said susceptor slabs.
 4. each said susceptor slab includingstructure cooperable with said means on said frame structure forseparably retaining said slabs engaged therewith,
 4. The reactor ofclaim 3 in which said susceptor slabs are supported by said supportingframe in a generally circular pattern surrounding the vertical axisthereof.
 5. each such slab being formed from a material which is opaqueto said radiant heat energy and which absorbs the same and is heatedthereby,
 5. The reactor of claim 1 in which said means defining saidreaction chamber depends from a base plate of said reactor and issupported thereby, and in which said susceptor means is suspended withinsaid reaction chamber from said base plate.
 6. The reactor of claim 1 inwhich said means defining said reaction chamber projects upwardly from abase plate of said reactor and is supported thereby, and in which saidsusceptor means projects upwardly into said reaction chamber.
 6. all ofsuch slabs having means on a surface thereof facing said heat source forseparably supporting thereon a plurality of substrates to be coated, 7.each such slab being selectively separable from said frame structure andbeing removable from said reaction chamber so that a plurality ofsubstrates to be coated may be positioned in engagement with or removedfrom such slab while the same is out of said reaction chamber, wherebyloading and unloading of said reaction chamber is facilitated.
 7. Thesusceptor means of claim 1 in which said supporting frame structurecomprises a. a vertically extending shaft, b. vertically spaced platemembers secured to said shaft, and c. retaining means on at least one ofsaid plate members for removably supporting such susceptor slab on saidframe structure.
 8. The susceptor means of claim 7 in which saidretaining means comprises at least one peg projecting from said oneplate member, said susceptor slab having at least one hole therein forreceiving a supporting peg therein when such slab is supported by saidframe member.
 9. The susceptor means of claim 8 in which each such pegis formed on the upper plate of said vertically spaced plate members.10. The reactor of claim 5 in which said susceptor means is verticallymovable from said reaction chamber so that said susceptor slab may bereadily separated from said supporting frame structure.
 11. The reactorof claim 6 in which said reaction chamber is removable from around saidsusceptor means so that said susceptor slab may be readily separatedfrom said supporting frame structure.